The present invention relates to a solar cell module for use in a photovoltaic power generation system, and more particularly relates to a solar cell module having a function of preventing a lowering of reliability due to water infiltration or separation.
FIG. 1 is a light-incident side plan view showing the structure of a conventional solar cell module; FIG. 2 is a cross section cut along the IIxe2x80x94II line of FIG. 1; and FIG. 3 is a cross section cut along the IIIxe2x80x94III line of FIG. 1.
In these figures, numeral 2 is a sheet-like substrate formed of a steel plate, and this substrate 2 has, on its both edges, engagement sections 2a and 2b to be engaged with adjacent other solar cell modules. A seal layer 3 that seals several to several tens pieces of crystalline, amorphous or other type of solar cell elements 3a, which are arranged on the same plane and wired in series or in parallel, to protect them is layered on the substrate 2, and a sheet-like light transmitting member 1 formed of a tempered glass material capable of transmitting light is layered on the seal layer 3, thereby constructing a solar cell module. The seal layer 3 is, formed of a synthetic resin such as PVB (polyvinyl butyral) and EVA (ethylene vinyl acetate).
The area of the substrate 2 is larger than the area of a layered body 4 constituted by layering the light transmitting member 1 and the seal layer 3. The engagement section 2a on one edge of the substrate 2 is formed by bending one edge of the substrate 2 upward and further bending it in a shape corresponding to an engagement section of an adjacent solar cell module, not shown, for example, in the shape of a square bracket with its opening facing the center side. Meanwhile, the engagement section 2b on the other edge of the substrate 2 is formed by bending the other edge of the substrate 2 downward and further bending it in a shape corresponding to an engagement section of other adjacent solar cell module, not shown, for example, by bending it in the direction of the substrate 2 to form an L shape.
In the event of installing solar cell modules having structures as described above on the roof of a house, for example, a plurality of solar cell modules are first arranged in a line in a girder direction on the eave side of the roof so that the engagement sections 2b are located on the eave side and then a plurality of solar cell modules are arranged in a line in a girder direction on the ridge side of the previously arranged solar cell modules so that their engagement sections 2b engage with the engagement sections 2a of the previously arranged solar cell modules, and solar cell modules are sequentially installed in the direction of the ridge. The edges, in the girder direction, of the solar cell modules installed in such a manner are provided with a decorative cover for preventing infiltration of rainwater and for improving the external appearance.
However, the conventional solar cell module does not have sufficient water-tightness and suffers from the disadvantage of a lowering of reliability of the solar cell module due to moisture infiltration from the end of the boundary between the light transmitting member 1 or the substrate 2 and the seal layer 3 and separation of the light transmitting member 1 or the substrate 2 and the seal layer 3. In particular, when the solar cell modules are installed on the roof of a house, the direction from the engagement section 2a to the engagement section 2b corresponds to the water running direction, and therefore, if there is a void between the engagement section 2a and an end face of the layered body 4, water is likely to stay in the void, resulting in a problem of facilitating moisture infiltration. In addition, there is a problem of facilitating infiltration of moisture into an end face of the layered body 4 on the engagement section 2b side due to the influence of wind.
An object of the present invention is to provide a highly reliable solar cell module by covering at least a part of end faces of a light transmitting member with a synthetic resin constituting a seal layer so as to waterproof the boundary between the light transmitting member and the seal layer, increase the contact surface between the light transmitting member and the seal layer, and prevent separation therebetween.
Another object of the present invention is to provide a solar cell module by waterproofing the solar cell module with the use of a synthetic resin constituting the seal layer so as to prevent water infiltration at low costs without additionally preparing a waterproof agent.
Still another object of the present invention is to provide a highly reliable solar cell module by filling the voids between raised sections formed at edges of the substrate and the end faces of the light transmitting member with a synthetic resin constituting the seal layer so as to prevent direct exposure of the boundary between the seal layer and the substrate to moisture, prevent moisture infiltration and separation at the boundary, increase the contact surface between the seal layer and the substrate and prevent separation at the boundary therebetween.
Yet another object of the present invention is to provide a highly reliable solar cell module by providing raised sections at edges of the substrate having engagement sections arranged in the eave-to-ridge direction so as to reduce the void between the ridge-side end face of a layered body and the substrate and prevent water from staying in the void when water runs from the ridge side to the eave side, and further prevent infiltration of moisture into the eave-side end face of the layered body due to the influence of wind.
A further object of the present invention is to provide a highly reliable solar cell module by arranging the raised sections to have a height equal to or more than the thickness of the seal layer and filling the voids between the raised sections and the end faces of the layered body up to a height equal to or more than the thickness with a synthetic resin constituting the seal layer so as to reduce the voids between the end faces of the layered body and the substrate, prevent water from staying in the voids, prevent deformation of the seal layer formed of the synthetic resin in a transverse direction and prevent breakage of the layered body and synthetic resin.
A solar cell module according to the first aspect of the present invention is a solar cell module constructed by sealing a plurality solar cell elements between a sheet-like substrate and a sheet-like light transmitting member, with a seal layer formed of a synthetic resin, wherein at least a part of end faces of the light transmitting member is covered with the synthetic resin constituting the seal layer.
According to the first aspect, by covering at least a part of the end faces of the light transmitting member with the synthetic resin constituting the seal layer, it is possible to prevent direct exposure of the boundary between the light transmitting member and the seal layer to moisture, prevent moisture infiltration, and prevent separation at the boundary. Moreover, since the contact surface between the light transmitting member and the seal layer is increased, it is possible to prevent separation at the boundary thereof. Furthermore, since waterproofing is made using the synthetic resin constituting the seal layer, there is no need to additionally prepare a waterproof agent.
A solar cell module according to the second aspect of the present invention is based on the first aspect, wherein edges of the substrate are provided with raised sections raised toward the light transmitting member side, and voids between the raised sections and the end faces of the light transmitting member are filled with the synthetic resin.
According to the second aspect, by providing the raised sections at edges of the substrate and filling the voids between the raised sections and the end faces of the light transmitting member with the synthetic resin constituting the seal layer, it is possible to prevent direct exposure of the boundary between the seal layer and the substrate to moisture, prevent moisture infiltration, and prevent separation at the boundary. Moreover, it is possible to increase the contact surface between the seal layer and the substrate and prevent separation at the boundary thereof. Furthermore, it is possible to reduce the voids between the end faces of the layered body and the substrate and prevent water from staying in the voids. In addition, it is possible to prevent deformation of the seal layer formed of a synthetic resin in a transverse direction and prevent breakage of the layered body and synthetic resin.
A solar cell module according to the third aspect of the present invention is based on the second aspect, wherein both edges of the substrate are provided with engagement sections that come into engagement with adjacent other solar cell modules, respectively, and the raised sections are formed on the edges having the engagement sections.
According to the third aspect, in the case where the engagement sections are arranged in the eave-to-ridge direction and water runs from the ridge side to the eave side, by providing the raised sections on the edges having the engagement sections, it is possible to reduce the void between the ridge-side end face of the layered body and the substrate and prevent water from staying in the void. Furthermore, it is possible to prevent infiltration of moisture into the eave-side end face of the layered body due to the influence of wind.
A solar cell module according to the fourth aspect of the present invention is based on the second or third aspect, wherein the raised sections have a height equal to or more than a thickness of the seal layer.
According to the fourth aspect, by making the height of the raised sections equal to or more than the thickness of the seal layer and filling the voids between the raised sections and the end faces of the layered body up to a height equal to or more than the thickness with the synthetic resin constituting the seal layer, it is possible to reduce the voids between the end faces of the layered body and the substrate and prevent water from staying in the voids, and also prevent deformation of the seal layer formed of the synthetic resin in a transverse direction and prevent breakage of the layered body and synthetic resin.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.